Casimir Forces in Nanostructures

Abstract

We present a theoretical calculation of Casimir forces in structures made of parallel slabs that can be made of dispersive and absorptive materials. The materials are characterized by the reflectivity amplitude coefficients of the vacuum modes between the slabs. In particular, we present results for an antisymmetric configuration in which one plate is a metal and the other one a dielectric material. As a reference, we also calculate the force for the symmetric case (two metallic or two dielectric slabs). Our results show that the Casimir force could have a relevant contribution to the interaction between the tip and sample in atomic force microscopy experiments.

Casimir force for absorbing media in an open quantum system framework: Scalar model

“…This was also extended to two identical absorbing superlattices [11]. Esquivel-Sirvent et al demonstrated an alternative Green-function approach that makes the quantization of the field within the slabs unnecessary and calculate the Casimir force in an asymmetric configuration [12] which was earlier considered only in the lossless case [13]. In Ref.…”

Casimir torque

“…However, recent works [16,17] have shown that if the theory is set up in terms of the reflection coefficients of the media, it is possible to decouple the calculation of the Casimir force from the calculation of the dielectric response of the materials. The so called scattering approach has permitted the calculation of the force for a wide class of systems simply by plugging into the resulting formulae the appropriate reflection amplitudes or surface impedances.…”

Excitonic effects in the Casimir force: A-exciton in CdS

“…We assume that the slabs are isotropic within the xy plane. We want to describe the electromagnetic fields only within vacuum, so we hide all the details of the field matter interaction within the slabs in their reflectivities r. The Casimir force between the twoslabs in a 1C1 space is given by [11] F Z ð N 0 dp…”

“…(1) may be derived using the fluctuation-dissipation theorem [14] or from Green's function calculation of the density of electromagnetic modes [11,13]. To apply Eq.…”

“…The original theory of Casimir was formulated for perfect conductors but Lifshitz calculated the force between two half-spaces with an arbitrary dielectric function [10]. For finite width layers the force was calculated until recently within different theoretical frameworks such as the fluctuation-dissipation theorem or a Green's function approach [11][12][13][14].…”